An unusual and enjoyable guided tour from the City of London to the Thames via the Barbican Highwalks. Includes maps, transport information, and the latest news from Twitter, all accessible on almost any smart phone.
The route starts in the City near Moorgate, and goes up off the street into the weird sci-fi world of the Barbican. You can stop off at the tropical Conservatory or the arts centre, and then the Roman remains around London Wall.
Coming back to ground level you go round St Paul's Cathedral, then down to the Millenium Bridge across the Thames.
The whole walk will take about an hour, or an afternoon if you stop off at one or more of the sights. It is a great family outing for the weekend.